Recorded shows stop or can't be watched.

The DVR shows that the program has been recorded but when selected it will only play part and refuse to play to the end or it won't start at all. When watching live TV on delay, it will suddenly jump to live (current position in show). A week ago, all recordings were lost. While watching a recording, it will often stop and display the menu; Watch next episode, Resume play, Start over, Erase, etc.